Collapsible bicycle trainer support structure

ABSTRACT

A frame used for mounting a bicycle eliminates bending loads typically observed in U-shaped frames, where an axial load is forced on the rear axle of a bicycle wheel. The frame uses the rear axle of the bicycle as a structural member to change the loading such that bending is eliminated. This reduces the requirements for the material strength of the frame. An axle interconnect system facilitates quick adjustment and mounting of the rear axle to the frame, and may use an existing skewer of the bicycle wheel. A resistance unit may be attached to the frame, or affixed to a joint in the frame, to facilitate use with a stationary trainer. Flexible frame members may be used to permit a rocking motion of the wheel when used for stationary training, or to allow for use on unlevel ground when training outdoors or for warmup before a race.

RELATED APPLICATIONS

This application claims priority to U.S. provisional patent application Ser. No. 62/778,010, titled “Collapsible Bicycle Trainer Support Structure” and filed on Dec. 11, 2018, which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

The present invention relates generally to exercise equipment, and specifically to a structure used to support the rear axle of a bicycle for the purposes of storage, indoor training or bicycle maintenance. The structure serves the purpose of providing a means to keep the bicycle upright or to keep the rear wheel elevated off the ground.

BACKGROUND

When storing a bike, or when using a bike for purposes including but not limited to stationary training, it is often required that the rear wheel is elevated off the ground to permit rotation of the wheel. In the instance of indoor training, a resistance mechanism, primarily targeted at increasing the difficulty of rotation of the rear wheel to replicate traditional riding energy expenditure, is affixed to a stationary frame. This combination of frame and resistance unit is traditionally referred to as a bike trainer in North America or a turbo or wind Trainer in the UK, and Oceania.

A standard stationary bike trainer frame design consists of a U-shaped frame, with legs that extend to support the U in an elevated orientation, with the base of the U located at or near the ground plane. At the top of the U, moving extensions which are specially designed to support the ends of the aforementioned trainer skewer are extended, thereby placing an axial compression load on the rear axle of the bike/skewer. In the case of thru-axle bikes, an updated interpretation of the quick release, compatible cone or dome shaped ends is used to mate with the compression force of the threaded extensions. This is highlighted in FIG. 1.

A commonality of all these mounting methods is that a substantial bending load must be carried through the arms of the U portion of the frame to exert the necessary axle compression. This bending load necessitates a heavy material gauge, and results in heavy weight, difficult processing, expensive materials and large shipping cost and weight.

SUMMARY OF THE EMBODIMENTS

This invention relates to a structure used to support a bicycle rear axle for the purposes of storage, indoor training or maintenance. The present invention alters the primary loading in the frame members from bending, using a “trainer skewer” or a thru-axle assembly used to support the bike primarily via an axial compression loading imparted by the frame structural members, to a tripod support mechanism affixed to the axle ends, thereby removing a large component of the axial loading on the trainer skewer and instead relying on triangulation using a truss structure. In this context, truss refers to a structure that is largely triangulated and provides the primary loading in a compression/tension modality. The reduction in bending load facilitates downgauging of material for improved storage dimensions, and a lighter shipping weight.

A further benefit of the present invention, is the ability to easily and consistently mount a bike into the aforementioned frame design using a detachable interconnect system, thereby improving end-user repeatability, minimizing time required to fit and remove the bike from the trainer. During storage, the dual tripod or poly-pod design efficiently folds to facilitate smaller storage size, improving user portability as well as reducing shipping cost and packaging. The term “tripod” will be used herein with the understanding that it implies additional potential members as well, and the term poly-pod representing a more general application of the concept of a tripod.

In accordance with an example embodiment of the present disclosure, there is a structural frame used to support the rear axle of a bike for the purposes of storage, maintenance or stationary training. The structural support frame is composed in such a way that the compression force on the rear axle of the bike is minimized and that the bending load on structural frame members (in the context of providing a skewer axial load) is thereby mitigated. The structural frame provides an interconnect with or near the rear axle of the bike in such a way that it may be stably supported. A primary functional novelty of the frame design is in triangulation of the supporting load through the rear axle, mitigating the bending moment created by clamping the axle in place. The frame is largely based on a tripod shape supporting each side of the axle, but polypedal or monopedal designs are also envisioned in the present disclosure, provided the structure results roughly in equivalence with a truss style triangulated structure created with the axle interconnects.

The frame may be constructed of multiple members, with the two halves, interconnected by one or more joints. Each half is composed of a polypedal frame, with folding joints allowing for easy collapse of the mechanism.

An additional embodiment of the present invention contains at least one solid interconnection between the two halves, forming a “V” or “U” shape between axle interconnects. The solid interconnection retains spacing of the frame and reduces degrees of freedom during setup, simplifying the process for the end-user.

The legs of the tripod may be positioned such that the center of force remains within the footprint established by placement of the frame members. Dynamic motions during training, such as sprints, or the rider leaning in one direction, may have the ability to shift the instantaneous resultant force from its typical centralized location, so for stability, the legs may be positioned in a way that excessive movement of this instantaneous center is unlikely to result in an unstable or structurally imbalanced platform.

The axle interconnects serve the function of fixing the axle in place as part of the structural mechanism. By providing connections at both ends, the frame becomes triangulated using the axle as a removable member. The triangulation of the frame removes the primary source of the bending loading, and provides an enhanced structural rigidity compared to a traditional frame. Furthermore, due to the triangulation, the interconnects need not impart a significant bending moment or compression force on the ends of the axle, but rather support it via point loads placed at each end of the axle. Any resultant bending moment imparted in the structural trainer frame may be primarily due to the offset between the center point of the tripod fixture and the interconnect location, and need not be transferred through the interconnect joint.

An exemplary embodiment of the device may include a mounting location on one of the frame members or joints for a cycling resistance unit, which turns a stationary frame into a bike trainer. The resistance unit may be affixed at the base joint, where the two sides of the frame interconnect, or may be affixed to any of the other members, such that the resistance unit is placed in a location appropriate for absorbing cycling energy, such as the periphery of the rotating wheel, or engaged with the drive chain.

The axle interconnects provide an interface location for affixing a bike. A release mechanism provides the opportunity to quickly and easily install or remove the bike from the frame.

An exemplary embodiment of the interconnect provides a yoke clamped between the head of a skewer or thru-axle and the dropout of the bike on each end of the axle. The yoke is firmly clamped in place, fixing the position of the trainer.

A further exemplary embodiment of the interconnect provides a ball lock mechanism with a sliding collar. Once locked in place, the axle may freely rotate within the ball-lock collar, but cannot move in an axial or radial direction relative to the rear axle. The sliding collar is moved to release the mechanism and remove the axle.

In accordance with a further exemplary embodiment of the interconnect provides a threaded connection to attach to the skewer/thru-axle. The end of the skewer/thru-axle is designed such that it may accept threads. An optional cone may be placed on the mating mechanism to help remove any bending loads from the extended fastener by seating the skewer/thru-axle within the cone.

A further exemplary embodiment of the interconnect provides a mating dovetail-type connection, allowing the axle ends to slide in place. A locking pin extends once the axle has been engaged, preventing the bike from sliding out of the interconnect body.

A further exemplary embodiment of the interconnect provides a mating dovetail that engages with a gate-latch type mechanism. With the latch engaged, an external force is required to open the latch and remove the bike, providing a safe mounting for usage in training.

In accordance with another exemplary embodiment, the members of the trainer may be made of a flexible material, primarily relating to the outermost supports, or outrigger elements. The outrigger elements are primarily used for stability, and manufacturing from a flexible material allows for the trainer to be placed on an uneven, or non-planar surface. This permits the trainer to be easily used in fields or uneven surfaces which are often used for warmup before competitions. Furthermore, the flexible outrigger elements allow for the trainer to rock side-to-side. This rocking motion replicates the motion of riding a bicycle on the road. This differs from previous implementations of a rocking motion in that the motion originates from the deflection of structural members at the outermost extent of the frame, rather than connecting two subframe assemblies via flexible or compressible members, such as United States Patent Application No. 2004/0053751A1 or U.S. Pat. No. 7,998,032 B2.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments of the present disclosure will now be described, by way of example, with reference to the accompanying drawings, in which:

FIG. 1 is a representative image of a conventional bike trainer frame with a significant axial compressive force placed through the rear axle of the bike, resulting in a large bending moment through the supporting U-shaped frame material;

FIG. 2a is a schematic view of an exemplary force vector diagram resulting from the proposed structural arrangement, with the weight of the rider and bicycle supported primarily as vertical loads through the top of two adjacent tripod or polypod/monopod structures; FIG. 2b is an exemplary view of the construction of the proposed support structure, as supported by 2 point loads at or near the rear axle, minimizing compressive and bending loads in the frame; FIG. 2c is a schematic force diagram illustrating how a triangulated pin jointed structure is able to strongly carry the axle without imposing bending loads in the supporting structure; FIG. 2d is an exemplary configuration of the structural frame design in a folded state, for transport, shipping or storage;

FIGS. 3a-3e are exemplary attachment or interconnect mechanisms to affix the rear axle of the bike to the structural frame. FIG. 3a shows an example of a mounting mechanism clamped between the existing bike skewer or thru-axle and the rear dropout of the bike frame, with the clamp load being provided by thread tension in the skewer or thru-axle; FIG. 3b shows an example of a ball-lock mechanism; FIG. 3c shows an example of a threaded mechanism attaching directly into a counter-threaded skewer cap; FIG. 3d shows an exemplary view of a slide lock/dovetail mechanism, using a locking pin to prevent accidental removal; FIG. 3e shows a gate-latch style mechanism, with a dovetail sliding interface;

FIG. 4a shows an exemplary view of the proposed structure used in a stationary training application, with a traditional tire roller/flywheel resistance mechanism (typical of a fluid- or wind- resistance mechanism) attached to the frame to interface with the tire; FIG. 4b is a schematic view of the proposed structure using an eddy current based magnetic resistance mechanism to interface with the wheel rim for resistance generation;

FIG. 5a-b show an exemplary flexible-outrigger based frame mechanism allowing for placement on uneven ground, or for the allowance of side-to-side rocking during pedaling and training.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Referring to FIG. 1, there is shown a contemporary bike trainer frame 1, which relies on extending elements 2 containing mounting cups 3 to compress the skewer 4 or thru-axle 5 on the rear axle of a bicycle 6. The bicycle 6 is held in place by a compressive loading on the skewer 4 or thru-axle 5 represented by a vector representation 7. The compressive force is required to be transmitted through the bike trainer frame 1, requiring a substantial material strength and thickness to facilitate the required stiffness. The compressive loading 7 on the skewer 5 is sufficient to hold the rear bike wheel 8 above the ground plane 9 and applying a roller 10 forcibly against the wheel 8. The resistive force provided for the cyclist is provided through the roller 10 and attached resistance mechanism 11. The trainer is balanced by a pair of extendable legs 12. The bending moment 13 is transmitted through the frame structure 1.

Referring to FIG. 2a-2b , there is shown a novel bike mounting frame. FIG. 2a schematically shows two tripod-like structures 14. Each of these structures supports approximately half of the load imparted by supporting the bike 15. The mounting frame relies on an interconnect 16 to provide a mechanism to contain and support the bike skewer 5 or thru-axle 6. Each of the two tripod-like structures 14 may be joined at one or more locations 17 to provide a triangulation of the frame structure 18 as shown schematically in FIG. 2c , eliminating or mitigating the bending moment 13 imparted by the axial axle compressive load 7. The resultant structure 19 in FIG. 2b may therefore be downsized to a lighter, smaller and cheaper material, enhancing portability of the frame 19.

Referring further to FIG. 2c , the triangulation of the frame is key to reducing material strength requirements. The skewer 5 or thru axle 6 becomes a removable part of the structure, but when held in place, a triangular truss structure 20 is formed, optionally repeated in several locations to facilitate different stability requirements.

Referring to the collapsed structure 30 in FIG. 2d , the two tripod-like structures 14 are in a folded state 15, connected by the joints 17 or a solid connection 31. The folded frame 30 is reduced in footprint minimizing the amount of space required for shipping, transportation or storage.

The rear axle interconnects 16 and corresponding axle mating surface 32 are shown in FIG. 3a-3e with different exemplary embodiments. These interconnects are shown as exemplary, but other embodiments are envisioned.

Referring to FIG. 3a , an exemplary embodiment of the axle interconnect 16 is shown with a yoke 33 clamped between the skewer 5/thru-axle 6 and the rear dropout 34 of a bike frame 35. The interconnect is repeated on each end of the axle 36 to support axle 36 by two-point loads rather than a cantilever arrangement. The clamp load is sufficient to prevent any relative motion between the bike frame 35 and the yoke 33.

In accordance with an alternative embodiment, FIG. 3b , a ball-lock mechanism 37 is interfaced with the axle mating surface 32. The ball-lock mechanism contains a sliding collar 38 used to lock the interconnect 16 to the axle mating surface 32. The sliding collar 38 is pulled in order to release the interconnect allowing the bike to be removed. Once engaged, relative axial or radial motion, relative to the bike axle 36 is not permitted in the interconnect 16, but rotation motion is not impeded.

In accordance with another alternative embodiment, FIG. 3c , a threaded interconnect is shown. This interconnect mechanism 16 relies on a threaded attachment 39 from the interconnect 16 to thread into the axle mating surface 32. The threaded attachment 39 is inserted sufficiently far that the gravitational load of the bike 15 is fully supported by the interconnect 16. To facilitate the strength of the joint, an optional conical mating surface 40 is shown interfacing further with the exterior surface axle mating surface 32. Although a conical shape is shown, it is understood that additional embodiments are possible. Tightening of the threaded attachment 39 into the threaded axle mating surface 32 forces the conical mating surface 40 of the interconnect 16 to support the loading of the bike 15, with the resultant loading of the threaded attachment 39 being in tension rather than bending.

In accordance with a further embodiment of the axle interconnect 16, a dove-tail like interface is shown, with the axle mounting surface 32 sliding inside a keyed channel 41. The shape of the channel allows only a sliding motion of the axle, and retains the ends of the axle mounting surface via grooves and teeth. Once in place, a locking pin 42 is extended to prevent further sliding motion of the axle mounting surface, limiting axial and radial motion of the axle relative to the center axis of the axle. It is understood that this is an exemplary description of the latch and that it may take other configurations to achieve the same purpose.

In accordance with another embodiment of the axle interconnect 16, a gate latch type mechanism 43 is used to secure the axle mounting surface 32 in place. A groove 46 is used to secure the location of the axle mounting surface 32 in an alignment landing 44, with a latching mechanism 45 rotating to secure the axle in place. The groove does not allow axial motion relative to the bike rear axle, while the latching mechanism 45 secures the axle to prevent radial motion in the direction of the alignment landing 44. The latching mechanism may be designed such that any forces in the direction of the alignment landing act in a direction aligned with the centre of rotation of the latching mechanism 45, thus preventing forces in the axle from loosening the latch.

In accordance with an additional embodiment of the frame assembly, a resistance unit may be attached such that the frame is used for stationary bike training. The resistance unit may be attached directly to one or more of the frame members such that it is able to come into proximity with the wheel 8. FIG. 4a shows an exemplary representation of a resistance unit 60 held onto a frame member 61 or a frame joint 62. The axle interconnects 16 firmly hold the rear wheel 8 in place such that the resistance unit 60 may press the requisite tire loading to facilitate usage for stationary bike training. In FIG. 4b is shown an alternative embodiment using a magnetic eddy current rim braking mechanism 63. It is understood that alternative embodiments, such as a resistance unit connecting directly to the bike chain (see U.S. Pat. No. 5,480,366) are imagined.

In reference to FIG. 5a , there is shown a bike frame 64 with flexible outrigger frame members 65 used to support the trainer on at least one balance point along an axis 62. The balance point 62 is used for rocking the trainer back and forth 66 around a pivot axis 62. These flexible members 65 are allowed to bend in response to the rocking motion 66 while keeping the triangulated frame arrangement 18 (in reference to FIG. 2c ) and maintaining the alignment of the wheel 8 and resistance unit 60. Furthermore, in reference to FIG. 5b , there exists the possibility of setting the frame on an unlevel surface 67. The flexible legs 65 adapt to the change in surface by extending/bending accordingly. To facilitate this process, an adjustable tether 68 may be used to change the offset in the legs relative to each side of the frame. This allows the balancing of forces and proper alignment of the frame when placed on an uneven surface 67. In this embodiment, folding of the trainer/stand 30 is permitted. A resistance unit 60 may be optionally attached to the frame to permit outdoor stationary exercising or warmup for races where a flat surface is not available.

In accordance with an additional embodiment of FIG. 5a , the flexible outrigger frame members 65 may instead be collapsible, such that the length changes to facilitate the rocking motion while remaining substantially straight.

While various exemplary embodiments of the frame assembly 9 are shown in the drawings with reference to a bicycle, it will be understood that certain adaptations and modifications of the described exemplary embodiments may be made as construed within the scope of the present disclosure. Although the term bicycle is used, the invention relates equally to use in human powered vehicles or cycles which may have 1 or more wheels. Therefore, the above discussed embodiments are considered to be illustrative and not restrictive. 

What is claimed is:
 1. A frame assembly used to mount a bicycle by or near a rear axle of the bicycle, comprising: a frame interconnect used to firmly mount the frame onto the rear axle of the bicycle and to lift the rear wheel off the ground; a skewer or thru-axle adapter attached to the bicycle at or near the rear axle to facilitate the attachment of the frame; an arrangement of structural members configured such that the rear axle becomes a removable member in the structure of the frame, facilitating triangulation of the loads and minimizing the bending force transmitted through any of the frame members; and a set of foldable legs permitting a tripod or poly-pod arrangement to support each end of the skewer or thru-axle adapter.
 2. The frame assembly of claim 1, wherein there is mounted an axle interconnect system affixing the axle as a removable member in the frame, but permitting angular rotation of the bicycle relative to the rear axle axis, but restricting axial and radial movement relative to the interconnect.
 3. The frame assembly of claim 2, wherein there is mounted a resistance unit to facilitate stationary bicycle training.
 4. The frame assembly of claim 3, wherein at least one of the legs is constructed to be flexible, permitting the use of the trainer on uneven ground by means of adaptation of the relative bending of the flexible members.
 5. The frame assembly of claim 3, wherein at least one of the legs is constructed to be of collapsible length, permitting the use of the trainer on uneven ground by means of adaptation of the length of the collapsible members.
 6. The frame assembly of claim 4, wherein a central tether is used to connect the flexible members and adjust the vertical alignment of the bicycle on uneven ground.
 7. The frame assembly of claim 5, wherein a central tether is used to connect the flexible members and adjust the vertical alignment of the bicycle on uneven ground. 